Burglar-alarm apparatus.



w. GABEL. BURGLAR ALARM APPARATUS.

APPLICATION FILED AUG-11,1914- 1,173,945, 4 Patented Feb. 29, 1916.

2 SHEETSSHEET I.

gwueyutoz W. H. GABEL.

BURGLAR ALARM APPARATUS.

Patented Feb. 29, 1916.

2 SHEETS-SHEET 2- WWI/1450969 Qwuwntoz UNITED s'rA'rns WILBUR H. GAB-EL, or KINTYRE, NORTH DAKOTA.

Specification of Letters Patent.

BURGLAR-ALARM APPARATUS.

- Patented Feb.29,1916.

Application filed August 11, 1914. Serial No. 856,187.

in burglar alarm apparatus and has particular application to electrically controlled apparatus of this character.

In carrying out the present invention,

it is my purpose to provide burglar alarm* apparatus which will embody an alarm circuit and a normally closed main circuit extending through the protected points and including a relay controlling the alarm cir cuit and holding the last-named circuit normally open and designed to close the same upon the breaking of the main. circuit at any one of the protected points, the relay holding the alarm circuit closed irrespective of the condition of the main circuit succeeding the breaking thereof.

With the above and other objects in view, the invention consists in the construction, combination and arrangement of parts hereinafter set forth in and falling within the '30 scope of the claims.

In the accompanying drawings: Figure 1 is a front elevation of the box carrying the alarm mechanism. Fig. 2 is a vertical sectional view therethrough. Fig. 3 is a horizontal sectional view through the same.

Fig. 4- is a front elevation of the relay removed from the box. Fig. 5 is a diagrammatic view of the apparatus.

Referring now to the drawings in detail,

' 1 designates a substantially rectangular box having the front wall hinged at one edge to the adjacent edge of one sidewall so as to provide a door 2 capable of swinging movement about the hinges to open and closed position and having the free edge thereof equipped with an eye 3 adapted to receive a hasp 1 carried by the outer surface of the adjacent side wall of the box to hold the door in closed position. Appropriately fastened to the back wall of the box 1 within the latter adjacent to the top of such box is a relay 5 comprising, a base plate 6 and electromagnets 7 secured to the base plate adjacent to the upper edge of the latter and 5 spaced apart horizontally. Projecting outwardly from the base plate 6 below the magnets 7 and adjacent to the opposite side edges of the base are arms 8 spaced apart horizontally and disposed in parallelism. The arms 8, adjacent to the outer extremities thereof, are formed with alining openings and threaded through these openings are set screws 9 having the confronting ends formed with axially alining depressions 10 designed to receive the opposite extremities of a pivot pin 11 upon which is fixed an arm .12 projecting at right angles to the pin and carrying an armature 13 designed to be held against the pole faces of the magnets 7 when the latter are ener 7 giz ed to hold the arm 12 in a vertical position, the arm dropping to horizontal position when the magnets are denergized. A cross bar 1 1 is disposed within the box and has the oppositeextremities thereof fas- 7 tened to the side walls of the box. The central portion of this cross bar is disposed in the path of movement of the outer end portion of the arm 12 and is provided with a contact 15 designed to be engaged by the arm 12 as the latter drops to horizontal position when relieved of the influence of the magnets ,7. The contacts 15 and arm 12 form the terminals of a local circuit 16 including asource of electrical energy as a number of dry cells 17 disposed within the box 1 and resting upon the bottom wall thereof and an alarm 18 in the form of a bell secured, to the outer side of the door 2 and designed to sound upon the closing of the local circuit 16 when the arm engages the contact 15. The magnets 7 of the relay are connected in series in a main circuit 19 extending through the protected points, such as the doors and windows of a domicile or outhouse and including a suitable source of electrical energy as a battery 20. i

From the foregoing description taken in connection with the accompanying drawings, the construction, mode of operation and manner of employing my invention will be readily apparent.

Themain circuit 19 is normally closed and in the event of the same being opened, the magnets 7 are denergized, thereby releasing the armature 13 and permitting the arm 12 to drop into engagement with the contact 15 and closing the local circuit 15 and sounding the alarm 18. A switch 21 is connected in the local circuit and located' when desired.

upon the cover or door 2 of the box-so that the local circuit may be opened and closed It will be seen that I have provided a burglar alarm apparatus wherein the movable contact in the local circuit gravitatesto closed position upon the denergization of the magnets of the relay and swings from a vertical position to a horizontal position so as to be out of the range of the magnetic lines of force of the magnetsof the relay, thereby holding the local circuit closed irrespective of the reclosing of the main circuit succeeding the opening thereof.

I-claim: 1

In burglar alarm apparatus, a box, a door closing one Wall of said box, a local alarm circuit including a bellfastened to the outer surface of said door, a source of energy within said box, a stationary contact disposedin a horizontal plane, a cross bar secured to the'opposite side walls of said box v and carrying said contact, a base plate secured to the wall of said box opposite from said door, electro-magnets secured to said plate adjacent to the upper edges thereof and spaced apart, horizontal arms projecting outwardly from said plate adjacent to thereof formed with alining openings, set screws threaded into said openings and having the confronting ends thereof formed with axially alining depressions, a horizonleasing. said armature whereby said arm willdrop to horizontal position toengage said statlonary contact, connections between the respective terminals of said'local alarm 011 cuit and said stationary contact and arm, and a main circuit extending through the the lower edge thereof and spaced apart horizontally and having the-outer ends protected points and normally closed and including said,magnets and adapted when opened to denergize said magnets.

In testimony whereof I afiix my signature 'in presence of two witnesses.-

WILBUR H. GABEL. Witnesses: I

H. C. GoRoER, J. HOLT. 

